Checking Sample Preparation and Measuring Conditions
Thermal conductivity tests are sensitive to many different factors like contact between probe and sample, unstable ambient temperature, sample size, heating power or water movement inside moist samples (convection). The TK04 software detects and eliminates some of these disturbances in the data automatically, and it provides tools to examine measurements for problems with sample preparation or measuring conditions and to correct or exclude them. This increases accuracy significantly.
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Measuring Software Includes Drift Correction
Measuring Software Includes Drift Correction 
It takes up to 24 hours for newly arrived samples to adapt to the laboratory temperature. If measurements are started too early, the temperature adjustment interferes with the heating curve, whose slope then appears too small or too large. This directly affects the thermal conductivity value. The TK04 software continuously monitors the temperature changes of the sample until the drift is small or steady enough to begin measuring. Data are automatically corrected for the remaining temperature drift.
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Optimal Choice of Evaluation Interval
The evaluation software compares the measuring data to the theoretical curve and automatically chooses the best (i.e. least disturbed) evaluation interval. Thermal conductivity is calculated from the time interval which best matches the theory.
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Additional Evaluations
The measuring curve is automatically evaluated in additional time intervals of different length and start time. The software only uses intervals where the temperature curve is sufficiently close to the theoretical curve. The results are saved for use with the presentation and analysis software TkGraph, which enables the user to examine measurements for influences of sample preparation and measuring conditions if required.
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Automatic Repetitions
The measuring software is able to execute measuring series with up to 99 single measurements fully unattended. The user chooses the number of repetitions. The software displays a result table and diagram, where the mean value of thermal conductivity and the variation in percent are immediately updated after each single measurement. While a measuring series is running, the user can always check the scatter of the thermal conductivity values. A scatter of more than ± 3% in most cases indicates instable ambient temperatures. This can be verified by examining the data with the TkGraph analysis program (included with the TK04 software package).
Presentation and Analysis Software TkGraph
TkGraph is part of the TK04 software package. Its purpose is documenting finished measurements and examining them for problems with sample preparation or measuring conditions. TkGraph provides tools for manually correcting or excluding disturbed measurements.
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Summary Plot
The Measuring Series Summary is based on the result files from TK04. Thermal conductivity values and several other parameters are plotted against the serial number of the measurements. Additionally, the mean value, the standard deviation and the variation are calculated and displayed in the Data Panel. The variation of thermal conductivity values, start and length of the intervals, the number of solutions found for each measurement and the LET values are important indicators of measurement quality. The Summary printout contains all necessary information for documentation purposes.
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Single Measurement Plot
These diagrams show in which parts of the measuring curves the evaluation software has found solutions, where the measuring data are differing more or less from the theoretical curve and how the distribution of the calculated thermal conductivity values differs from an ideal, undisturbed curve. The TK04 manual includes detailed instructions how to use these diagrams for identifying typical problems like insufficient contact between probe and sample, unstable ambient temperature, too small samples or inadequate heating power.